Nonlinear Dynamical Behavior of the Deep White Matter during Head Impact
Nonlinear Dynamical Behavior of the Deep White Matter during Head Impact
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DOI：
10.1103/physrevapplied.12.014058
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发表时间：
2019-07-30
影响因子：
4.6
通讯作者：
Kurt, Mehmet
中科院分区：
文献类型：
--
作者：
Abderezaei, Javid;Zhao, Wei;Kurt, Mehmet
创伤性脑损伤（TBI）是一个主要的公共卫生问题，在美国每年影响多达300万人，尽管近年来进行了大量的研究工作，但我们对损伤原因的物理理解仍然相当有限。在本文中，我们通过模态分析和先进的有限元（FE）模拟的非线性动力学行为的脑颅骨系统的特征。我们观察到的非线性行为，在深白质（WM）结构附近的硬脑膜褶皱，约30%的主导模式之间的能量重新分配。我们发现的剪切波重定向的证据附近的镰和天幕（约15度的轴向和8度的冠状面）作为一个结果的几何非线性。大脑镰模式形状的转变，这是垂直于大脑的变形，导致几何非线性效应在大脑镰-脑组织边界。这伴随着脑组织下方天幕的侧向滑动，从而在其与大脑深部区域的界面处引起更高的局部应变。我们观察到，高主应变的大脑深部区域与所识别的非线性区域相吻合。脑组织非线性行为的发生与先前报道的脑震荡阈值密切相关，这表明损伤机制与潜在的非线性脑生物力学之间可能存在联系。
Traumatic brain injury (TBI) is a major public health concern, affecting as many as 3 million people each year in the U.S. Despite substantial research efforts in recent years, our physical understanding of the cause of injury remains rather limited. In this paper, we characterize the nonlinear dynamical behavior of the brain-skull system through modal analysis and advanced finite-element (FE) simulations. We observe nonlinear behavior in the deep-white-matter (WM) structures near the dural folds, with an energy redistribution of around 30% between the dominant modes. We find evidence of shear-wave redirection near the falx and the tentorium (approximately 15 degrees in the axial and 8 degrees in the coronal plane) as a result of geometric nonlinearities. The shift in the falx mode shape, which is perpendicular to the deformation of the brain, causes geometrical nonlinear effects at the falx-brain tissue boundary. This is accompanied by a lateral sliding of the tentorium below the brain tissue, which induces higher local strains at its interface with deep regions of the brain. We observe that deep regions of the brain with high principal strains coincide with the identified nonlinear regions. The onset of nonlinear behavior in brain tissue is closely associated with the previously reported concussion thresholds, suggesting a possible link between the damage mechanism and the underlying nonlinear brain biomechanics.